High reflector tunable stress coating, such as for a MEMS mirror

Abstract

An optical device having a high reflector tunable stress coating includes a micro-electromechanical system (MEMS) platform, a mirror disposed on the MEMS platform, and a multiple layer coating disposed on the mirror. The multiple layer coating includes a layer of silver (Ag), a layer of silicon dioxide (SiO 2 ) deposited on the layer of Ag, a layer of intrinsic silicon (Si) deposited on the layer of SiO 2 , and a layer of silicon oxynitride (SiO x N y ) deposited on the layer of Si. The concentration of nitrogen is increased and/or decreased to tune the stress (e.g., tensile, none, compressive).

1. An apparatus, comprising:
 a base of a photonic device; 
 a multiple layer coating disposed on the base, wherein the multiple layer coating includes a first layer of silver (Ag) having a physical thickness of at least approximately one hundred nanometers, a second layer of silicon dioxide (SiO 2 ) having an optical thickness of a first percentage of a quarter of a wavelength of interest within a band of wavelengths of interest, a third layer of silicon (Si) having an optical thickness of a second percentage of a quarter of the wavelength, and a fourth layer of silicon oxynitride (SiO x N y ) having an optical thickness of a third percentage of a quarter of the wavelength and a ratio of N y  in the fourth layer of SiO x N y  includes values within a range from approximately sixty percent N y  to twenty percent N y . 
 
   
   
     2. The apparatus of  claim 1 , wherein the second layer of SiO 2  includes a physical thickness of approximately two hundred seventy nanometers and the third layer of Si includes a physical thickness of approximately fifty nanometers. 
   
   
     3. The apparatus of  claim 2 , wherein the fourth layer of SiO x N y  includes physical thickness within a range from approximately one hundred nanometers to one hundred ten nanometers. 
   
   
     4. The apparatus of  claim 1 , wherein the base includes a substrate. 
   
   
     5. The apparatus of  claim 4 , wherein the substrate includes silicon. 
   
   
     6. The apparatus of  claim 1 , wherein the optical thickness of the second layer of SiO 2  is approximately one quarter of a wavelength of interest within the band of wavelengths of interest. 
   
   
     7. The apparatus of  claim 1 , wherein the first layer of Ag includes a physical thickness of at least approximately one hundred nanometers. 
   
   
     8. The apparatus of  claim 1 , wherein the optical thickness of the third layer of Si is of approximately 0.41 quarter of the wavelength of interest within the band of wavelengths of interest. 
   
   
     9. The apparatus of  claim 1 , wherein the optical thickness of the fourth layer of SiO x N y  is an approximately 0.44 quarter of the wavelength of interest within the band of wavelengths of interest. 
   
   
     10. An apparatus, comprising:
 a base of a photonic device; 
 a multiple layer coating disposed on the base, wherein the multiple layer coating includes a first layer of gold (Au) having a physical thickness of at least approximately one hundred nanometers, a second layer of dielectric material having an optical thickness of a first percentage of a quarter of a wavelength of interest within a band of wavelengths of interest, a third layer of silicon (Si) having an optical thickness of a second percentage of a quarter of the wavelength, and a fourth layer of silicon oxynitride (SiO x N y ) having an optical thickness of a third percentage of a quarter of the wavelength and a ratio of N y  in the fourth layer of SiO x N y  includes values within a range from approximately sixty percent N y  to twenty percent N y . 
 
   
   
     11. The apparatus of  claim 10 , wherein the second layer of dielectric material includes a layer of silicon dioxide (SiO 2 ). 
   
   
     12. The apparatus of  claim 11 , wherein the second layer of dielectric material includes a layer of silver dioxide (AgO 2 ) disposed on the layer of SiO 2 . 
   
   
     13. The apparatus of  claim 11 , wherein the second layer of dielectric material includes a layer of silver dioxide (AgO 2 ) disposed between the SiO 2  and the layer of and the layer of Au.